What is Grimoire?

Etymology

From Old French gramaire, 

from Ancient Greek γραμματικός (grammatikos, “knowing how to read and write”). 

Noun

grimoire (plural grimoires)

1.    A book of instructions in the use of magic or alchemy, especially summoning demons.

The name "Grimoire" is derived from the word "Grammar". A grammar is a description of a set of symbols and how to combine them to create well-formed sentences. A Grimoire is, appropriately enough, a description of a set of magickal symbols and how to combine them properly. Most of the texts linked below are descriptions of traditional European ritual magick, which is based on Judeo-Christianity. Even though this must not be confused with neo-Paganism, many of the neo-Pagan traditions use similar rituals and techniques, albeit with a different (usually Celtic) vocabulary.

Note: These historical texts are presented for research and entertainment purposes only;

2. A grimoire /ɡrɪmˈwɑr/ is a textbook of magic. Such books typically include instructions on how to create magical objects like talismans and amulets, how to perform magical spells, charms and divination and also how to summon or invoke supernatural entities such as angels, spirits, and demons. In many cases, the books themselves are also believed to be imbued with magical powers, though in many cultures, other sacred texts that are not grimoires, such as the Bible, have also been believed to have magical properties intrinsically; in this manner while all books on magic could be thought of as grimoires, not all magical books could.

While the term grimoire is originally European and many Europeans throughout history, particularly ceremonial magicians and cunning folk, have made use of grimoires, the historian Owen Davies noted that similar such books can be found all across the world, ranging from Jamaica to Sumatra, and he also noted that the first such grimoires could be found not in Europe but in the Ancient Near East.